Here is a further update on the PCB progress.
The PCB is a 4 layer design and we will be finalising the PCB layout in the next 24 hours and the PCB layout will be commited to a PCB board run and a production prototype could be assembled in as early as weeks times. So things are starting to really more along now.

If any of you would like to be placed on an email update list please drop me an email and I will place you on it.

The SmartDAC Project is one step closer to completion with the
first production prototype shown below.
We still have some more software development to do, before final release.
But we are expecting to have it available by Christmas 2009 if all goes well.
More information to follow soon.

If you would like to be placed on an update notification list, please get in contact with me via the following email address aussieamplifiers@bigpond.com.

The Burson opamp may well sound better, but it is not a practical device to use
in a commercial product, such as the SmartDAC.
It much too large.
The LME49740 is an excellent device and does sound very good indeed and because of the small packaging is we suited to the application it is applied to in the SmartDAC. :)

rabbitz

18th February 2010 07:08 AM

The Burson op amps can sound very good indeed but need rails higher than ±15V to perform at their best and even then there are op amps that can do a better job more simply, with less heat and smaller. I've used both the Burson op amps and their buffer but were replaced by op amps.

Is the LME49740 similar to the LM4562 but a quad?

The Saint

18th February 2010 08:16 AM

Quote:

Originally Posted by rabbitz
(http://www.diyaudio.com/forums/showthread.php?p=2089447#post2089447)

The Burson op amps can sound very good indeed but need rails higher than ±15V to perform at their best and even then there are op amps that can do a better job more simply, with less heat and smaller. I've used both the Burson op amps and their buffer but were replaced by op amps.

Is the LME49740 similar to the LM4562 but a quad?

o

Hi Peter

So what opamp did you replace them with in the end?

Too answer your question , The LME49740 is the quad version of the LM4562.
The idle current in these opamps is quite high and it makes the 14 pin package, run quite warm indeed. :)

Originally Posted by The Saint
(http://www.diyaudio.com/forums/showthread.php?p=2089488#post2089488)

o

Hi Peter

So what opamp did you replace them with in the end?

Hi Anthony

I went with the AD825 for a while and then changed to the LM4562. Very happy with the result and these were used on the output stage of CD players plus one buffer. I tried lots of others such as LM6171, OPA627, OPA2604, OPA2132, OPA2134, AD843 etc and were mostly used to replace 5532 or 4558 in CD players.

I found the LM4562 very forgiving in application and didn't need any special tricks or power supply requirements so tended to drop straight in without hassles. I've had it running with various voltages from ±5V to ±15V. There's something very neutral about this op amp that doesn't get in the way like most others. Most of the others have good sonics in various areas but there was always a down side... that included the Burson op amp as can be a bit over blown in certain applications. The LM4562 may not be the best op amp in the world but works extremely well for my needs and tastes.

rabbitz

18th February 2010 11:24 AM

Quote:

Originally Posted by pcsl999
(http://www.diyaudio.com/forums/showthread.php?p=2089540#post2089540)